Method for forming monolithic pipe in situ



DCC- l.. v. THoMAsoN METHOD FOR FORMING MONOLITHIC PIPE IN SITU 3 SheetsSheet 2 Filed April 1968 THOMA SON TQ" g Amy v.

/NVENTOR ATTORNEYS L. V. THOMASON METHOD FOR vFORMIIIG MONOLITHIC PIPE IN SITU Filed April 12, 1968 3 Sheets-Sheet 3 m G n w l i. .da

LARRY l/. THOMASO/V /4 TTORNEVS United States Patent O 3,551,537 METHOD FOR FORMING MONOLITHIC PIPE IN SITU Larry V. Thomason, 528 E. Lansing Way, Fresno, Calif. 93704 Filed Apr. 12, 1968, Ser. No. 720,936 Int. Cl. B28b 2l 88; E04b 1/16 U.S. Cl. 264-33 9 Claims ABSTRACT OF THE DISCLOSURE A method for forming monolithic pipe utilizing a tubular shell having a longitudinal gap extending the length thereof and telescopically related at its ends to other similar shells, the shells so related being supported in the bottom of a formed trench on stable supports and in turn supporting a traveling hopper receiving plastic cementitious material and flowing it around the shells, the shell being made of a flexible material and having latch devices therewithin for selectively maintaining the shells in open gap position, the shells being contractible to relatively closed gap position for reducing the diameter thereof and held in such position by the latch devices for shell removal after the formed pipe has hardened, the contracted shells being interconnected at adjacent ends to produce a lost motion effect for reducing the amount of adjacent shell overlap in response to pulling of the shells from an end thereof.

BACKGROUND OF INVENTION The present invention relates to the manufacture of monolithic pipe in situ, typified by U.S. Pat. Nos. 2,731,- 698 and 3,205,550, and more particularly to a method and apparatus for forming extensive lengths of such pipe about a plurality of pipe supporting form members or shells in a trench and withdrawing such shells in considerable lengths for later reuse in making more pipe.

Various attempts have been made to provide methods and machines for continuously forming pipe of plastic cementitious materials. Such methods and machines have heretofore possessed merit to varying degrees but also have possessed disadvantages inherent in their manner of use. For example, in machines where the placing of supporting forms ahead of the formed pipe is carried on simultaneously with the formation of such pipe, the speed with which a pipe may be formed is limited to the speed at which the additional forms may be placed. In other cases, the speed of pipe formation is affected because of the requirement that only a small section of pipe can be formed at a time, rather than continuously. In still other cases, where the pipe supporting forms are of the reusable knock-down type, they usually involve a multiplicity of separate parts which require additional handling and possess the attendant possibility of loss with a resultant hampering of the progress of the work. Such forms also require considerable labor for their assembly and disassembly, particularly, the withdrawal thereof one at a time from the finished pipe. Further, many such machines have been unable to form such pipe with desired precision and control and thus have not been able to attain necessary quality in the pipe produced.

SUMMARY OF INVENTION It is therefore an object of the present invention to provide a method and apparatus for forming pipe in situ which is simpler in operation and involves a minimum number of separate parts.

Another object is to provide an apparatus for forming pipe by which various phases of the work can be carried out simultaneously with attendant economies in construction.

Another object is to provide an apparatus for forming a continuous length of pipe in a rapid and reliable manner.

Another object is to provide an apparatus for producing a monolithic pipe having good flow characteristics.

Another object is to provide a pipe supporting form in which the several parts thereof are interconnected to preclude loss or misplacement of detached parts.

Another object is to provide pipe supporting forms which can be contracted and connected together for withdrawal of a considerable length of such forms at one time from the finished pipe.

Another object is to provide pipe supporting forms which are connected with a predetermined amount of end overlap for forming the pipe and are withdrawn from the formed pipe in connected relation but with a reduced amount of end overlap for facilitating such withdrawal.

Another object is to provide a support device for supporting a pipe form in a stable and reliable manner for maintaining the same in proper relation to the bottom and sidewalls of a trench.

These and other objects and advantages are achieved by the provision of a method and apparatus for forming monolithic pipe of plastic cementitious material which utilizes a pipe supporting form member consisting essentially of a tubular shell having a longitudinal gap extending the length thereof, the shell being made of a stiilly resiliently flexible material whereby it may be contracted to close the gap and reduce the cross section thereof, the shell having therewith latch means disposable across the gap for holding it in open gap or closed gap condition, the shells being adaptted to be telescopically connected in open gap condition with a predetermined amount of end overlap determined by abutment means within the shell. After the pipe has been formed around the shells, they are contracted and the overlapped ends the shells are interconnected by hooks and pivoted D-rings which provide a lost motion effect for reducing the amount of end overlap in response to the pulling apart or tensioning of the shells whereby the shells can be easily pulled out of one end of the formed pipe. The connected shells are supported in proper relation to a trench on stable supporting plates of unique shape and serve to support a traveling frame having a hopper which receives the cementitious material and flows it around the connected shells, the traveling frame having adjustable wings for lengaging the sidewalls of the trench for centering and stabilizing the frame as it travels along on the interconnected forms.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary side elevation of an apparatus embodying the principles of the present invention and utilized to practice the method thereof.

FIG. 2 is a foreshortened horizontal section of a tubular form shell member of the yapparatus of the present invention showing the manner of latching the member to provide different cross sectional dimensions thereof.

FIG. 3 is a vertcal section showing the shell member within the formed pipe and contracted to its smaller cross sectional dimension.

FIG. 4 is a plan view of a hand operated trowel of the apparatus.

FIG. 5 is a fragmentary detail plan view showing the connection made between the shell members for withdrawal thereof from the formed pipe.

FIG. 6 is a larger scale longitudinal vertical section of a portion of FIG. 1 illustrating structural details thereof.

Patented Dec. 29, 1970 FIG. 7 is a fragmentary vertical section taken generally along line 7-7 of FIG. 6.

FIG. 8 is a vertical section taken generally along line 8-8 of FIG. 6 and further including the hand operated trowel.

FIG. 9 is a fragmentary vertical section taken generally along line 9-9 of FIG. 6.

FIG. 10 is a top plan view of the traveling hopper mechanism with parts thereof omitted.

DESCRIPTION OF EMBODIMENT Referring to the drawings, there is illustrated in FIG. 1 an apparatus 11 embodying the principles of the present invention and for practicing the method thereof. The apparatus consists essentially of a plurality of tubular pipe supporting forms or shells 12 disposed on spaced apart supports 14 in a ditch or trench T and supporting a traveling hopper mechanism 16 for owing plastic cementitious material C around the shells to form a monolithic pipe P therearound. The trench T is formed in the usual manner with vertical sidewalls and semi-cylindrical bottom having a center line on a gradient declining in the desired direction of iiow in the pipe to be formed, indicated by the arrow F. The supports 14 iare placed in the trench bottom at predetermined interivals and proper grade to support the shells 12 above the bottom concentrically thereof in accordance with the desired thickness of the pipe P. The ends of the shells 12 are telescopically related and overlap a predeterminedl amount with the outer overlapping end 18 of each shell disposed upstream from the inner overlapped end 20 thereof. The telescoped ends of the shells thus create minute steps or shoulders 22 which face upstream and cause the pipe P to be formed with slight steps or shoulders S which face downstream and hence do not impede the flow of uids in the pipe. The hopper mechanism 16 is made to travel upstream in the direction of the arrow M so as to cross each step 22 in a descending fashion and not disturb the overlapped relation of the shells. As will later appear, the shells can be contracted to smaller cross sectional dimensions and interconnected for removal from the pipe P in sections for later reuse in forming more pipe.

FIG. 2 shows one of the shells 12 in horizontal section on a larger scale. It is to be noted that each shell is slitted lengthwise to provide a longitudinal slot or gap 24 which is coextensive the length of the shell. Each shell is of substantially cylindrical shape and is made of a stifi'iy tiexible material permitting deformation of the member so that the cross sectional shape or diameter thereof can be reduced by closing the gap, as shown in the righthand portion of FIG. 2 and in FIG. 3. Latch devices 26 are provided for maintaining the shells in open or closed gap condition. In the use of the shells to form pipe in the 24-36 inch diameter range, shells eight feet long made from 0.14 inch thick steel or 0.19 inch thick aluminum have been successfully employed, the aluminum shell providing an extremely smooth pipe interior. The gap 24 can vary in width, as desired, from six to eight inches, being excellently suited to most situations.

Each of the latch devices 26 has a pair of legs 28 and 30 angularly related and generally defining the letter L. Leg 28 is sufciently rigid to resist compression and has a hook-like projection or finger 32', whereas leg 30 is of lighter construction for resisting tension and has a projection or finger 34. At the juncture of the legs 28 and 30, the latch device is provided with a perforation 36 in which is loosely received a U-shaped member 38, such as a staple or the like, suitably secured to the inner surface of the shell 12, as by welding or the like. The staple 38 is disposed to one side of the gap 24 and serves as a pivot for the latch device. Secured to the shell on the opposite side of the gap is a keeper 4,0 having an aperture 42, best seen in FIG. 8. The latch device can be pivoted to dispose leg 28 thereof across the gap 24 with the finger 32 in the aperture 42 for maintaining the shell in expanded or open gap condition and providing a greater cross sectional shape or configuration. The latch device can also be disposed so that the short leg 30 thereof is across the gap 24 with the finger 23 inserted in the aperture 42. With such disposition, it is readily apparent that the gap 24 is substantially closed and the cross sectional shape or diameter of the shell is considerably reduced.

The shell 12 can be contracted to its reduced cross sectional configuration by any suitable means. Since such reduction must be accomplished from within the shell, secured to the interior thereof is a pair of upstanding posts 44 to which any tension producing means can be connected, preferably a winching device 46, as shown in FIG. 3. The device 46 has a U-shaped frame 4.7 in which one of the posts 44 is received, best seen in FIG. 2, the other post 44 being received in the looped end of a line or cord 48. The line passes under a roller 49 on the frame 47 and is wound about a spool, not shown, to which a ratchet wheel 50 is secured. The spool and wheel are journaled on a shaft 51 which also serves as pivot for a lever 52 carrying a pawl 53 engaged with the ratchet wheel for imparting motion thereto in response to swinging of the lever. A detent 54 pivoted to the frame 49 also engages the ratchet wheel. Thus, swinging of the lever causes the line 48 to be wound up and tensioned for drawing the posts 44 together to close the gap 24 after which the finger 34 of the latch device 26 is inserted in the aperture 42 in the keeper 40. After the latch device is in place, the detent 54 is released and the winching device is removed from the posts 44.

Inviting attention to FIGS. 4 and 8, there is shown a smoothing tool or trowel 56 of low silhouette or shallow U-shaped cross section with a leading end 58, side lips or wings 60 and a pair of handle bars 62. During formation of the pipe P, the trowel is disposed in the gap 24 supported on the edges thereof by the lips or wings. The trowel is grasped by a workman within the shell for smoothing the cementitious material below the gap, the low silhouette thereof providing for passage of the trowel under the latch devices 26. It will be appreciated that the trowel S6 can be manipulated to round off or practically eliminate the step S in that portion of the pipe P between the edges of the gap 24 for further improving the ow characteristics of the pipe, if so desired.

Referring to FIGS. 2 and 8, it will be noted that each support 14 is made up of a concavo-convexly curved plate 64 and a pair of posts or studs 66 projecting from the concave surface thereof, the plate having a curvature conforming to the outer surface of the finished monolithic pipe P, the posts being disposed substantially radially and of a length equal to the thickness of the finished pipe. The plates 64 are placed in the trench T with the posts 66 located substantially equidistantly from the center line thereof whereby the respective shell 12 is centered and supported thereon in a stable manner concentrically of the curved bottom of the trench. The supports 14 are incorporated into the finished pipe P.

Referring to FIG. 6, fixedly secured to the shell 12 opposite its gap 24 and adjacent to its end 18 is an angular bracket or hook 68 against which the end 20 of the next shell abuts for predetermining the amount of overlap of these ends. As indicated earlier after formation of the pipe P, the shells are contracted and interconnected for removal in sections. It is therefor desirable to reduce the amount of end overlap to provide a degree of articulation between the ends for easier withdrawal of the shells from the pipe, particularly, where the pipe has been formed in a curving trench. Accordingly, there is pivotally mounted ou each shell, adjacent to its end 20, a D-ring 70 which engages with the hook 68 on the next shell, as shown in FIG. 5, to define the amount of such reduced overlap. Initially, the D-ring depends out of connection with the hook, as shown in FIG. 6, and is swung upwardly to encompass the hook, as shown in dotted lines in FIG. 5. The pivotal mount of the D-ring is provided with a degree of friction and is sufficiently stiff to retain the D-ring in hook encompassing position. It will be appreciated that in such position the shells can move relative to each other a predetermined amount before the hook and D-ring make engaging contact. The interconnection thus possesses a lost motion effect.

Inviting attention to FIGS. 6-9, the traveling hopper mechanism 16 is provided with a body or box frame 72 having parallel side walls 74 with inwardly bent front ends, 76, and transverse intermediate and rear walls 78 and 80, respectively. The walls 74, 78 and 80 define a chamber or hopper Which receives the cementitious material C. The lower edge of the rear wall 80 is curved to be substantially concentric with the shell 12, to which edge an arcuate trowel or molding portion 82 is secured, as by Welding or the like. The molding portion 82 is further interconnected with the rear wall 80 by a pair of braces 84, each including threaded rods 86, welded or otherwise secured to the rear wall and the molding portion respectively. The threaded rods are interconnected by a turnbuckle 88 for adjusting the molding portion relative to the shell to provide a degree of convergence for effecting a molding or troweling effect upon the top portion of the pipe P as it is being formed.

The wall 78 has a lower curved edge and secured thereto and to the sidewalls 74 is an arcuate platform 90. The frame 72 is supported for travel on the shells 12 by a pair of spaced apart skids 92, secured to the read wall 80, and a pair of rollers 94 mounted on the underside of the platform 90. As seen in FIGS. 9 and l0, the skids 92 are vertically disposed and have a thin blade shape with sharpened front and rear edges for facilitating the ow of cementitious material therearound. To preclude the cementitious material from flowing under the platform and fouling the rollers 94, an arcuate skirt or seal 95 is attached to the wall 78 and has a curvature which is conformed to the upper portion of the shell 12. The rollers 94 are located on each side of the skids 92 and are radially disposed so that the axes of rotation thereof are perpendicular to longitudinal planes intersecting generally at the axis of the shell, as will be appreciated on viewing FIG. 7. Such an arrangement supports the frame 72 on the shells in a stable manner.

For centering the frame 72 in the trench T, adjustable guiding wings 96 are pivotally mounted on the rear edges of the sidewalls 74 and engage the sidewalls of the trench, as shown in FIG. 9. Each wing has an arm 98 at an angle thereto and rigid therewith with which a setscrew 100 is threadedly connected and engages the rear Wall 80` for maintaining the wing at any desired position of adjustment. A coil spring 102 is interconnected between the wall 80 and the wing for maintaining the setscrew in such engagement.

Secured to the sidewalls 74, over the platform 90, is a at floor 103 on which a pair of bearing mounts 104 are fastened which journal a winching drum 106 driven by a compressed air motor 108 through a gear reduction mechanism 110, as shown in FIG. 10. The motor is connected by a hose 112 to a container 114 supported on the floor 103 and having compressed air therein. As will be appreciated from viewing FIG. 6, a line or cable 116 has one end thereof anchored to a point ahead of the hopper mechanism and the other end thereof connected to the drum 106 whereby rotation of the drum winds the line thereabout for advancing the hopper mechanism toward the anchor point.

The cementitious material C is received in a hopper defined by the walls 74, 78 and 80. Such materialcan be delivered directly into such hopper or through the intermediary of a feed control bin or funnel 118 removably supported on the sidewalls 74 over the hopper in any suitable manner. As shown in FIG. 6, the funnel has downwardly converging walls 120 and end walls 122 to which a bottom plate 124 is pivoted. A control lever 126 is fixed to the bottom plate for tilting it and controlling the ow of material passing between its edges and the walls 120. The bottom plate may be held at any desired position of feed adjustment by engaging the control lever with projections or stops 128 on an end wall of the funnel.

Plastic cementitious material C from the funnel 118 passes to the receiving hopper and ows gravitationally around the shell -12 therebelow. Such ow is assisted by means of a pair of compressed air vibrators 130 attached to the wall 78 and connected by hoses 132 to the container 114. For further assisting the flowing of the cementitious material around the shells, there is provided a power driven tamping mechanism which includes a rock shaft 134 journaled in bearing mounts 136 secured to the walls 78 and 80. Fixed to the shaft 134 and disposed transversely thereof is a double-ended cross arm 138 having a pair of tamping legs or tampers 140 pivoted to the ends thereof, as shown in FIG. 8.

Viewing FIGS. 8 and l0, fixed to one end of rock shaft 134 is a rock arm 142 which is pivoted to one end of a link 144, the other end of the link being pivoted to a crank arm 146 fixed to one end of a rotatable shaft 148 journaled in a pair of bearing mounts 150 secured to the oor 103. The shaft 148 is driven by a compressed air motor 152 connected by a hose 154 to the compressed air container 114. Thu's, operation of the motor 152 serves to rock the shaft 134 and impart oscillation to the arm 138 for moving the tamping legs 140 up and down for flowing and tamping the cementitious material around the 'shells 12.

It is understood, of course, that the apparatus of the present invention can be used in a U-shaped form, instead of a trench, and that the supports 14 and wings 96 can function to center and stabilize the shells 12 and the traveling hopper mechanism 16 therein.

OPERATION The operation of the apparatus of the present invention is believed to be clearly apparent and is briefly summarized at this point. After the trench T has been excavated to the desired shape with a substantially semi-cylindrical bottom having a central line at desired gradient, the supports 14 are located at intervals in the bottom of the trench, about four feet apart in the case where the length of the shell 12 is eight feet. Each support is set at the proper grade with the posts 66 located substantially equidistantly from the center line of the bottom of the trench and radially with respect to the center of curvature thereof. Shells 12 are then placed on the supports 14 in open gap condition with the gaps 24 substantially centered between the posts 66 and the ends of the shells thereof overlapping the maximum extent as defined by abutment of the end 20 of each shell with the hook 68 of the adjoining shell, as shown in FIG. 6. A suicient number of shells are usually interconnected in this manner for forming an approximately 300 foot length of monolithic pipe. The traveling hopper mechanism 16 is placed on the downstream end of the length of interconnected shells and the guiding wings 96 are adjusted to dispose the mechanism centrally wlth respect to the shells and the trench. The line or cable 116 is anchored to a point upstream. The apparatus is now ready to commence the formation of monolithic pipe about the shells.

Cementitious material such as plastic concrete or the like is delivered into the funnel 118 which controls the feed thereof into the hopper therebelow. With the vibrators 130 and the tamper legs 140 functioning, the cementitious material flows around the shells for forming the monolithic pipe P thereabout, rotation of the winch 106 serving to move the mechanism 16 upstream in the direction of the arrow M at a controlled speed. In the meantime, a Worker inside the shell manipulates the trowel 56 for forming that part of the pipe P between the edges of the gap 24. If desired, the formation of the pipe P may commence before the full 300 foot length of shells have 7 been laid, thus permitting placing of the supports 14 and the completion of the interconnection of the shells upstream while pipe is being formed downstream.

After the cementitious material has set to form a hardened pipe, a worker or workers operate inside the shells l2 for progressively unlatching, contracting and relatching the shells and placing each D-ring 70 in encompassing relation to the hook 68 of the adjoining shell. About 100 feet of the contracted shells are normally so interconnected, after which a line is attached to the downstream shell and such length of shells is withdrawn from the downstream end of the linished pipe P at one time. This results in the D-rings progressively engaging the respective hooks for reducing the amount of end overlap of the shells. The shells thus pass over the steps S in descending fashion and are carried downstream for use in forming more pipe, as necessary. Another 100 foot length or so of shells is withdrawn in a similar manner until the shells have been withdrawn completely from the finished pipe.

In the meantime, the shells previously withdrawn are reconnected downstream in open gap condition and supported on new supports 14 at the proper grade and desired interval. The upstream shell of such new length of interconnected shells is expanded within the downstream end of the previously finished pipe. Again, starting from the downstream end of the new length of connected shells, cementitious material is liowed about the shells to form a new length of monolithic pipe which is joined to the hardened pipe. After the new length of pipe has hardened, the process is repeated until the job is completed. If desired, the shells withdrawn from the downstream end of the finished pipes can be carried upstream and attached to the expanded shell projecting from the finished pipe for progressively interconnecting the shells in open gap condition on supports 14 previously laid by a party working ahead of the shell interconnecting party. Thus, various phases of the work may be engaged in and proceed simultaneously.

There has thus been provided a method and apparatus for forming monolithic pipe in situ which operates in a simple manner for rapidlylforming extensive lengths of monolithic pipe.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred method and apparatus, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent methods and apparatus.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A method of forming monolithic pipe in situ com- Y prising forming a trench, interconnecting a plurality of elongated transversely contractible internal forms in endto-end substantially rigid overlapping relation, positioning the forms in the trench in spaced relation to the bottom and sides thereof, flowing a hardenable material into the trench around the forms, contracting the forms after the material has hardened, disconnecting said forms, reconnecting the forms with relatively loose connections for relative flexing and drawing the interconnected forms longitudinally from the hardened material while contracted.

2. The method of claim 1 wherein the forms are interconnected in telescopic relation with a predetermined amount of overlap for the flowing of the hardenable material therearound, and are drawn from the hardened pipe interconnected by lost motion interconnections for reducing the amount of overlap and facilitating the drawing thereof.

3. The method of claim 1 wherein the ends of the interconnected forms overlap in a common direction and the forms are positioned in a trench having a bottom at a desired flow gradient, and the outer overlapping end of each form is disposed upstream and with the adjoining shell forms a shoulder in the pipe which faces downstream.

4. The method of claim 3 wherein the interconnected contracted forms are drawn from the downstream end of the hardened pipe for traversing the shoulders therein in a descending fashion.

5. The method of claim 1 wherein the trench has a semi-cylindrical bottom, the forms are substantially cylindrical shells positioned on supporting lmeans which include arcuate plates having curvatures substantially conforming to the bottom of the trench and converging members extending substantially radially therefrom for supporting the associated shell in substantially centered relation with the bottom of the trench, the supporting means being incorporated into the pipe in the formation thereof.

6. The method of claim 1 further including withdrawing the interconnected contracted forms from the downstream end of the pipe formed by the hardened material, positioning the withdrawn forms in interconnected expanded condition with the upstream shell thereof eX- panded within the downstream end of the hardened pipe, and producing a pipe of hardenable `material about the forms from the downstream end thereof to a juncture with the previously hardened pipe.

7. The method of claim 1 in which the forms are contracted from internally thereof.

8. The method of claim 1 in which the forms are of substantially cylindrical resiliently exible sheet material having longitudinal gaps defined by spaced edges of the sheet material and the forms are disposed in the trench with the gaps downwardly disposed.

9. The method of claim 8 in which the forms are latched internally in expanded position before the hardenable material is flowed into the trench and latched internally in contracted position after the material has hardened and before the forms are drawn therefrom.

References Cited UNITED STATES PATENTS 1,540,185 6/1925 Richards 249-179 3,032,852 5/1962 Hanson 25-32 3,205,550 9/1965 Martin 25-32 ROBERT F. WHITE, Primary Examiner l. R. THURLOW, Assistant Examiner U.S. Cl. X.R. 

